1. Technical Field
The present disclosure relates to a signal processing method, and more particularly to a positioning apparatus and a signal processing method thereof.
2. Related Art
A relative positioning based on Global Navigation Satellite Systems (GNSS) carrier phase observation value is the most popular precise positioning method. In this method, the coordinates of the observation stations can be measured precisely at centimeter level. When the satellite signal is shielded by objects like trees or is interfered or interrupted by ionospheric effect, multipath effect, problems of a receiver or the like, the receiver cannot lock the signal and thus cannot lock the satellite. As a result, the received signal generates a deviation of an integer cycle, which is called as cycle slip.
The cycle slip is a measurement error commonly appearing in the relative positioning. Therefore, the cycle slip must be compensated in positioning for ensuring the positioning accuracy. There are various methods for correcting the cycle slip. Most of these methods detect discontinuous points of the signal on a time axis. Here, the observation time must be precise to ensure that the discontinuity phenomenon is caused by the cycle slip instead of by non-uniform time scales. Due to this limitation, the low-price GNSS receiver is hard to be applied in the high precise positioning situations of GNSS. Therefore, methods for correcting the cycle slip are still needed improvement.